Pentaerythritol esters of mercapto acids plus long chain fatty acids

ABSTRACT

This invention relates to compositions of the formula: ##STR1## wherein n is 0 to 2 and at least 1 and not more than 2n + 2 of the A groups are ester radicals of the structure ##STR2## wherein R is a straight chain or branched, saturated or unsaturated hydrocarbon radical containing 11 to 19 carbon atoms and at least 2 and not more than 2n + 3 of the A groups are ester radicals of the structure ##STR3## wherein m is 0 to 1. The composition is formed by reacting one mole of a mono, di- or tri-pentaerythritol of the formula: ##STR4## WHEREIN N IS 0-2 WITH 2N + 4 MOLES OF A MIXTURE OF MONOCARBOXYLIC ACIDS FROM THE GROUP CONSISTING OF (A) AT LEAST 1 AND NOT MORE THAN 2N + 2 MOLES OF RCOOH wherein R is a straight chain or branched, saturated or unsaturated hydrocarbon radical containing 11 to 19 carbon atoms and (b) at least 2 and not more than 2n + 3 of HSCH 2  (CH 2 ) m  COOH wherein m is 0 to 1. In the present invention it is preferred to react only one acid from each of the mercapto and the long chain fatty acid group members. However, more than one acid from each group member can be reacted if desired.

This is a division of application Ser. No. 623,216 filed Oct. 16, 1975,now U.S. Pat. No. 4,039,723 .

This invention relates to pentaerythritol esters. More particularly,this invention relates to pentaerythritol esters used in radiationcurable coatings which impart improved slip characteristics contributedby the fatty acid moiety present in the instant pentaerythritol esters.

The use of radiation curable compositions in roll coating substrates hasgained wide interest. This is due to the fact that in many cases nosolvent is necessary and, therefore, solvent recovery and its adjunctpollution problems are not present. Further, radiation curable coatingsdo away with the necessity of heating or drying ovens and theirconcurrent problems of pollution and high energy requirements.

The object of the instant invention is to provide a pentaerythritolester which when used in combination with a polyene can provide aradiation curable coating which has improved slip, i. e., lubricity,characteristics.

The above and other objects are obtained herein by a pentaerythritolester composition of the formula: ##STR5## wherein n is 0 to 2 and atleast 1 and not more than 2n + 2 of the A groups are ester radicals ofthe structure ##STR6## wherein R is a straight chain or branched,saturated or unsaturated hydrocarbon radical containing 11 to 19 carbonatoms and at least 2 and not more than 2n + 3 of the A groups are esterradicals of the structure ##STR7## wherein m is 0 to 1.

The composition is formed by reacting one mole of a mono, di- ortri-pentaerythritol of the formula: ##STR8## wherein n is 0-2 with 2n +4 moles of a mixture of monocarboxylic acids from the group consistingof (a) at least 1 and not more than 2n + 3 moles of RCOOH wherein R is astraight chain or branched, saturated or unsaturated hydrocarbon radicalcontaining 11 to 19 carbon atoms and (b) at least 2 and not more than2n + 3 of HSCH₂ (CH₂)_(m) COOH wherein m is 0 to 1. In the presentinvention it is preferred to react only one acid from each of themercapto and the long chain fatty acid group members. However, more thanone acid from each group member can be reacted if desired.

Operable fatty acids of the formula RCOOH herein include, but are notlimited to, lauric, myristic, palmitic, stearic, isostearic, oleic,linoleic and arachidic acid·β-mercaptopropionic and mercaptoacetic acidare the operable mercapto acids in this invention.

The reaction is preferably carried out in a solution which forms anazeotrope with water. Aliphatic or aromatic hydrocarbon solvents such ashexane, benzene, xylene and the like are operable as solvents in theinstant invention.

In practicing the invention, an acid catalyst, e. g., p-toluene sulfonicacid, methane sulfonic acid, sulfuric acid and the like, is employed incatalytic amounts.

The reaction is performed at the refluxing temperature of the mixture.The reaction period is from about 16 to 48 hours depending uponreactants and catalysts employed.

In carrying out the reaction the solvent, pentaerythritol, catalyst andthe mercapto and the long chain fatty acids are added concurrently tothe reactor. The reactor is then heated to the reflux temperature of themixture with stirring and the reaction is continued until water is nolonger evolved indicating completion of the reaction. Although themercapto and the long chain fatty acid can be added concurrently inpracticing the invention, the acids can also be added sequentially. Thatis, for example, one could add the fatty acid to the reactor containingthe pentaerythritol, solvent and catalyst, heat the reactor to therefluxing temperature of the mixture with stirring and continue thereaction until water is no longer evolved. At this point one could thenadd the mercapto acid, maintain the reaction at the refluxingtemperature of the mixture with stirring and continue the reaction untilwater was no longer evolved. On completion of the reaction the mixturebecomes a homogeneous solution.

The amount of acid added can range from the stoichiometric amount withinthe range set forth supra up to an amount in excess thereof, e. g., 20%excess.

Following the reaction, the ester product is recovered by washing withwater or washing with an aqueous base followed by a water wash andthereafter removing the solvent by stripping under vacuum or otherconventional means.

The following examples will explain, but expressly not limit, theinstant invention. Unless otherwise noted, all parts and percentages areby weight.

EXAMPLE 1

Dipentaerythritol (1.20 mols, 305 gms), stearic acid (1.32 mols, 375gms), 2000 ml of toluene, and 12 gms of p-toluenesulfonic acid werecombined in a 5-liter 3-neck flask equipped with stirrer, Dean Starktrap and addition funnel. The mixture was stirred and heated to vigorousrefluxing until no longer collected in the trap. This required 4 hoursreaction time, and a total of 21 ml of water was collected. Using theadditional funnel, 700 grams (6.60 mols) of β-mercaptopropionic acid wasadded all at one time. Heating and refluxing was continued until waterwas no longer evolved, requiring 16 hours additional reaction time. Thereaction mixture became a homogeneous solution at this time. Aftercooling the mixture was washed successively with 2500 ml distilledwater, 2500 ml of 5% NaHCO₃ solution, and 2 × 2500 ml of water. Thetoluene solution containing the product was separated and dried withanhydrous MgSO₄, treated with about 5 gms of decolorizing carbon andfiltered through a Celite-coated filter. The toluene was flashed off ona rotary evaporator, with water aspiration, then finally stripped with ahigh vacuum pump through a liquid N₂ cooled trap. The viscous yellowishresidue gradually changed to a waxy semi-solid on cooling. The resultantproduct weighed 1125 g. (96% yield) and analyzed 4.68 meq. of SH/g. Thetheoretical SH for the structure of the product: ##STR9## is 5.20 meq.SH/g.

EXAMPLE 2

To a glass-lined steam jacketed reactor piped up in series with a heatexchanger, decanter and pump to allow recycling of the solvent and waterwithdrawal was charged 350 pounds benzene, 100.3 pounds triple pressedstearic acid, 118.2 pounds β-mercapto proprionic acid, 50 poundspentaerythritol and 5.4 pounds of p-toluene sulfonic acid. The reactantswere mixed for one hour at which time heat was applied to raise thetemperature to 185°-190° F. The reaction was continued under refluxingconditions with stirring for 37 hours at which time the acid number was0.174. The reactor was cooled to room temperature and the contents ofthe reactor was subjected to repeated batch washes with deionized wateruntil the acid number was 0.031. The solvent was then stripped from thereaction at a temperature of about 165-170° F under vacuum over a periodof four hours. The resulting product weighed 238 pounds (87% yield) andanalyzed for 4.44 meq. SH/g. and 0.077 meq. acid/g. The theoretical SHfor the structure of the product: ##STR10## is 4.50 meq. SH/g.

EXAMPLE 3

A glass-lined steam jacketed reactor equipped with stirrer was piped upin series with a heat exchanger, decanter and pump which allowed thesolvent to be recycled back to the reactor. To the reactor was charged600 pounds toluene, 130 pounds of dipentaerythritol (containing 22.13meq. OH/g.), 132 pounds of triple pressed stearic acid (containing 3.63meq. carboxyl/g.), 7.8 pounds of p-toluene sulfonic acid and 259 poundsof β-mercapto propionic acid (containing 9.25 meq. OH/g.). The decanterwas filled with 72.5 pounds of toluene to aid recycle. Stirring wascommenced and the reactor was heated in the range 210°-216° F for aperiod of 22 hours. The reactor was cooled down and repeated washes ofdeionized water were charged to the reactor until the acid number of thereaction was 0.01. The reactor was then reheated to 165° F and thetoluene solvent was stripped off under vacuum. The resultant product wascollected and weighed 425 pounds (76.6% yield) and analyzed for 4.82meq. SH/g. and 0.013 meq. acid/g. The theoretical SH for the structureof the product: ##STR11## is 5.20 meq. SH/g.

The fatty acid-containing pentaerythritol esters of the instantinvention can be used in conjunction with polyenes to form radiationcurable coatings having improved slip properties. The polyenes operableherein include, but are not limited to, those disclosed in U.S. Pat. No.3,661,744 and U.S. Pat. No. 3,898,349, both incorporated herein byreference.

Generally stated, the present invention provides a curable compositionof improved slip properties which comprises 98 to 2 percent by weight ofsaid composition of a polyene component and 2 to 98 percent by weight ofsaid composition of a polythiol, i. e., fatty acid-containingpentaerythritol ester, component. A photosensitizer is added when curingis by U. V. light.

The polyene component may be represented by the formula:

    [A--X].sub.m

wherein m is an interger of at least 2, wherein X is a member selectedfrom the group consisting of: ##STR12##

In the groups (a) to (g), h is an integer from 1 to 9; R is a radicalselected from the group consisting of hydrogen, fluorine, chlorine,furyl, thienyl, pyridyl, phenyl, and substituted phenyl, benzyl andsubstituted benzyl, alkyl and substituted alkyl, alkoxy and substitutedalkoxy, and cycloalkyl and substituted cycloalkyl. The substituents onthe substituted members are selected from the group consisting of nitro,chloro, fluoro, acetoxy, acetamide, phenyl, benzyl, alkyl, alkoxy andcycloalkyl. Alkyl and alkoxy have from one to nine carbon atoms andcycloalkyl has from three to eight carbon atoms.

The members (a) to (g) are connected to [A] through divalent chemicallycompatible derivative members. The members (a) to (g) may be connectedto [A] through a divalent chemically compatible derivative member of thegroup consisting of Si(R)₂, carbonate, carboxylate, sulfone, ##STR13##alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl,urethane and substituted urethane, urea and substituted urea, amide andsubstituted amide, amine and substituted amine, and aryl and substitutedaryl. The alkyl members have from one to nine carbon atoms, the arylmembers are either phenyl or naphthyl, and the cycloalkyl members havefrom three to eight carbon atoms with R and said members substitutedbeing defined above. B is a member of the group consisting --O--, --S--,and --NR--.

The member [A] is a polyvalent; free of reactive carbon-to-carbonunsaturation, free of highly water-sensitive members; and consisting ofatoms selected from the group consisting of carbon, oxygen, nitrogen,chlorine, bromine, fluorine, phosphorus, silicon and hydrogen. Saidatoms are combined to form chemically compatible members of the groupconsisting of carbonate, carboxylate, carbonyl, ether, silane, silicate,phosphonate, phosphite, phosphate, alkyl and substituted alkyl,cycloalkyl and substituted cycloalkyl, aryl and substituted aryl,urethane and substituted urethane, urea and substituted urea, amine andsubstituted amine, amide and substituted amide, hydroxyl, heterocycliccarbon containing radical, and mixtures thereof; said substituents onsaid members being defined above.

The polyene component has a molecular weight in the range from about 64to 20,000, preferably about 200 to about 10,000; and a viscosity in therange from essentially 0 to 20 million centipoises at 70° C as measuredby a Brookfield Viscometer.

The member [A] of the polyene composition may be formed primarily ofalkyl radicals, phenyl and urethane derivatives, oxygenated radicals,and nitrogen substituted radicals. The member [A] may also berepresented by the formula: ##STR14## wherein j and k are integersgreater than 1; R₂ is a member of the group consisting of hydrogen andalkyl having one to nine carbon atoms; R₃ is a member of the groupconsisting of hydrogen and saturated alkyl having one to nine carbonatoms; R₄ is a divalent derivative of the group consisting of phenyl,benzyl, alkyl, cycloalkyl, substituted phenyl, substituted benzyl,substituted alkyl and substituted cycloalkyl; with the terms alkyl,cycloalkyl and members substituted being defined above.

Representative formulas for polyenes operable in the present inventionmay be prepared as exemplified below:

I. Poly (alkylene-ether) Polyol Reacted with Unsaturated MonoisocyanatesForming Polyurethane Polyenes and Related Polymers ##STR15##

II. Poly (alkylene-ether)Polyol Reacted with Polyisocyanate andUnsaturated Monoalcohol Forming Polyurethane Polyenes and RelatedPolymers ##STR16##

In the above formulas, the sum of x + y + z in each chain segment is atleast 1; p is an integer of 1 or more; q is at least 2; n is at least 1;R₁ is selected from the group consisting of hydrogen, phenyl, benzyl,alkyl, cycloalkyl, and substituted phenyl; and R₇ is a member of thegroup consisting of CH₂ ═CH--CH₂ --_(n), hydrogen, phenyl, cycloalkyl,and alkyl.

The class of polyenes of this invention derived from carbon-to-carbonunsaturated monoisocyanates may be characterized by extreme ease andversatility of manufacture when the liquid functionality desired isgreater than about three. For example, consider an attempted synthesisof a polyhexene starting with an -OH terminated polyalkylene ether hexolsuch as "Niax" Hexol LS-490 (Union Carbide Corp.) having a molecularweight of approximately 700, and a viscosity of 18,720 cps at 20° C. Anattempt to terminate this polymer with ene groups by reacting 1 mole ofhexol with 6 moles of tolylene diisocyanate (mixed-2,4, 2-6-isomerproduct) and 6 moles of allyl alcohol proceeded nicely but resulted in aprematurely chain extended and crosslinked solid product rather than anintended liquid polyhexene. Using the monoisocyanate route, however,this premature chain extension may be avoided and the desiredpolyurethane-containing liquid polyhexene may be very easily prepared bya simple, one-step reaction of one mole of hexol with 6 moles of allylisocyanate. This latter polyhexene has the added advantage of beingcured using the teachings of this invention to a non-yellowingpolythioether polyurethane product. Similarly, the unsaturatedmonoisocyanate technique may be used to prepare liquid polyenes fromother analagous highly functional polyols such as cellulose, polyvinylalcohol, partially hydrolized polyvinyl acetate, and the like, andhighly functional polyamines such as tetraethylene pentamine,polyethyleneimine, and the like.

A general method of forming one type of polyene containing urethanegroups is to react a polyol of the general formula R₁₁ (OH)_(n) whereinR₁₁ is a polyvalent organic moiety free from reactive carbon-to-carbonunsaturation and n is at least 2 with a polyisocyanate of the generalformula R₁₂ (NCO)_(n) wherein R₁₂ is a polyvalent organic moiety freefrom reactive carbon-to-carbon unsaturation and n is at least 2 and amember of the group consisting of an ene-ol, yne-ol, ene-amine and yneamine. The reaction is carried out in an inert moisture-fre atmosphere(nitrogen blanket) at atmospheric pressure at a temperature in the rangefrom 0° to about 120° C for a period of about 5 minutes to about 25hours. In the case where an ene-ol or yne-ol is employed, the reactionis preferably a one step reaction. Where an ene-amine or yen-amine isused, the reaction is preferably a two step reaction wherein the polyoland the polyisocyanate are reacted together and thereafter preferably atroom temperature, the ene-amine or yne-amine is added to the NCOterminated polymer formed. The group consisting of ene-ol, yne-ol,ene-amine and yne-amine are usually added to the reaction in an amountsuch that there is one carbon-to-carbon unsaturation in the group memberper hydroxyl group in the polyol and said polyol and group member areadded in combination in a stoichiometric amount necessary to react withthe isocyanate groups in the polyisocyanate.

A second general method of forming a polyene containing urethane groups(or urea groups) is to react a polyol (or polyamine) with anene-isocyanate or an yne-isocyanate to form the corresponding polyene.The general procedure and stoichiometry of this synthesis route issimilar to that described for polyisocyanates in the preceding. In thisinstance, a polyol reacts with an ene-isocynanate to form thecorresponding polyene. It is found, however, that products derived fromthis route, when cured in the presence of an active light source and apolythiol, may form relatively weak solid polythioether products. Toobtain stronger cured products, it is desirable to provide polarfunctional groupings within the main chain backbone of the polymericpolyene. These polar functional groupings serve as connecting linkagesbetween multiple repeating units in the main chain series, and serve asinternal strength-reinforcing agents by virtue of their ability tocreate strong interchain attraction forces between molecules of polymerin the final cured composition.

Another group of polyenes operable in this invention includes thosepolyenes in which the reactive unsaturated carbon-to-carbon bonds areconjugated with adjacent unsaturated groupings. Examples of operablereactive conjugated ene systems include, but are not limited to thefollowing: ##STR17## A few typical examples of polyenes which containconjugated reactive double bonds groupings such as those described aboveare the triacrylate of the reaction product of trimethylolpropane with20 moles of ethylene oxide, pentaerythritol tetraacrylte,trimethylolpropane trimethacrylate and triacrylate, triacrylate ofisocyanurate, tetramethaacrylate, and the like.

The aforesaid polyenes containing ester groups may be formed by reactingan acid of the formula R₁₃ (COOH)_(n) wherein R₁₃ is a polyvalentorganic moiety free from reactive carbon-to-carbon unsaturation and n isat least 2, with either an ene-ol or yne-ol. The reaction is carried outat atmospheric pressure at a temperature in the range from 0° to about120° C for a period of 5 minutes to 25 hours. Usually the reaction iscarried out in the presence of a solvent, e.g., benzene at refluxingtemperature. The water formed is azeotroped off of the reaction.

Another method of making an ester containing polyene is to react apolyol of the formula R₁₁ (OH)_(n) wherein R₁₁ is a polyvalent organicmoiety free from reactive carbon-to-carbon unsaturation and n is atleast 2; with either an ene-acid or an yne-acid. The reaction is carriedout in the same manner as set out above for the ester-containingpolyenes.

A further group of polyenes which are operable in the present inventionincludes unsaturated polymers in which the double or triple bonds occuralso within the main chain of molecules. These are derived primarilyfrom standard diene monomers such as polyisoprene, butadiene,styrene-butadiene rubber, isobutylene-isoprene rubber, polychloroprene,styrene-butadiene-acrylonitrile rubber and the like unsaturatedpolyesters, polyamides, and polyurethanes derived from monomerscontaining "reactive" unsaturation. As examples, adipic acid-butenediol,1,6-hexanediamine-fumaric acid and 2,4-tolylene diisocyanatebutenediolcondensation polymers and the like are operable.

In forming the polyenes of the present invention, catalytic amounts of acatalyst may be employed to speed up the reaction. This is especiallytrue in the case where an ene-ol is used to form the polyene. Suchcatalysts are well known to those in the art and include organometalliccompounds such as stannous octoate, stannous oleate, dibutyl tindilaurate, cobalt acetylacetonate, ferric acetylacetonate, leadnaphthanate and dibutyl tin diacetate. The polyene/polythiol mole ratiosare selected so as to provide a solid, self-supporting cured productunder ambient conditions in the presence of actinic or high energyionizing radiation.

The curing reaction can be initiated by either U. V. radiation or highenergy ionizing radiation. The U. V. radiation can be obtained fromsunlight or special light sources which emit significant amounts of U.V. light having a wavelength in the range of about 2000 to 4000 Angstromunits. When U.V. radiation is used for the curing reaction, a dose of0.0004 to 60 watts/centimeter² is employed.

When U.V. radiation is used for curing, a photosensitizer is added tothe composition. Preferred photocuring rate accelerators orphotosensitizers are the aldehyde and ketone carbonyl compounds havingat least one aromatic nucleus attached directly to the ##STR18## group.Various photosensitizers include, but are not limited to, benzophenone,acetophenone, o-methoxybenzophenone, acenapthenequinone, methyl ethylketone, valerophenone, hexanophenone, γ-phenylbutyrophenone,p-morpholinopropiophenone, dibenzosuberone, 4-morpholinobenzophenone,4'morpholinodeoxybenzoin, p-diacetylbenzene, 4-aminobenzophenone,4'-methoxyacetophenone, benzaldehyde, α-tetralone, 9-acetylphenanthrene,2-acetylphenanthrene, 10-thioxanthenone, 3-acetylphenanthrene,3-acetylindole, 9-fluorenone, 1-indanone, 1,3,5-triacetylbenzene,thioxanthen-9-one, xanthene-9-one, 7-H-benz-[de]anthracen-7-one,1-naphthaldehyde, 4,4'-bis(dimethylamino) benzophenone, fluorene-9-one,1'-acetonaphthone, 2'-acetonaphthone, 2,3-butanedione,triphenylphosphine, tri-o-tolyphosphine, acetonaphthone,2,3-butanedione, benz[a]anthracene 7,12 dione, etc. which serve to givegreatly reduced exposure times and thereby when used in conjunction withvarious forms of energetic radiation yield very rapid, commerciallypractical time cycles by the practice of the instant invention. Thephotosensitizers are usually added in an amount ranging from 0.0005 to50% by weight of the polyene and polythiol.

The radiation curable compositions of the instant invention can also becured by high energy ionizing irradiation. A preferred feature of theionizing irradiation operation of the instant invention is treatmentwith high energy particle irradiation or by gamma-rays or X-rays.Irradiation employing particles in the instant invention includes theuse of positive ions, (e.g., protons, alpha particles and deuterons),electrons or neutrons. The charged particles may be accelerated to highspeeds by means of various voltage gradient mechanisms such as a Van deGraaff generator, a cyclotron, a Cockroft Walton accelerator, a resonantcavity accelerator, a betatron, a G.E. resonant transformer, asynchrotron or the like. Furthermore, particle irradiation may also besupplied from radioactive isotopes or an atomic pile. Gamma rays orX-rays may be obtained from radioisotopes (e.g. cobalt 60) or byparticle bombardment of suitable target material (e.g., high energyelectrons on a gold metal target).

The dose rate for the irradiation operable to cure the coating in theinstant invention is in the range 0.00001 to 1000 megarads/second.

The amount of ionizng radiation which is employed in curing theradiation curable material in the instant invention can vary betweenbroad limits. Radiation dosages of less than a megarad up to 10 megaradsor more for electrons are operable, preferably 0.02 to 5 megarads energyabsorbed are employed. For gamma-rays or X-rays, radiation dosages inthe range 0.0001 to 5.0 megarads energy absorbed are operable. Theirradiation step is ordinarily performed under ambient temperatureconditions but can be performed at temperatures ranging from below roomtemperatures up to temperatures of 90° C.

The compositions to be radiation cured, i.e., converted to solidcoatings, in accord with the present invention may, if desired, includesuch additives as antioxidants, inhibitors, activators, fillers,pigments, dyes, antistatic agents, flame-retardant agents, thickeners,thixotropic agents, surface-active agents, viscosity modifiers,plasticizers, and the like within the scope of this invention. Suchadditives generally are preblended with the polyene of polythiol priorto coating it on the substrate. The aforesaid additives may be presentin quantities up to 500 parts or more per 100 radiation curablecompositions by weight and preferably 0.0005 to 300 parts on the samebasis. The type and concentration of the additives must be selected withcare so that the final composition remains radiation curable underconditions of exposure.

The curable liquid polymer compositions of the instant invention priorto curing can be pumped, poured, brushed, sprayed, doctored, rolled,trowelled, dipped-coated, extruded or gunned into place into cavities,into molds, or onto vertical or horizontal flat surfaces in a uniformfashion. Following such application curing in place to a solid resin oran elastomer can be made to occur very rapidly. The compositions can beapplied to various substrates and adhere well to glass, wood, metals,concrete, certain plastics, paints, enamels, fabrics, paper, paperboard, porcelain, ceramics, brick, cinder block, plaster and vinyl floortile.

The liuid polythioether-forming components and compositions of theinstant invention can, prior to curing, be admixed with or blended withother monomeric and polymeric materials such as thermoplastic resins,elastomers or thermosetting resin monomeric or polymeric compositions.The resulting blend can be subjected to conditions for curing orco-curing of the various components of the blend to give cured productshaving unusual physical properties. Examples of the classes of thematerials which can be admixed, blended or co-cured with thepolythioether-forming compositions of the instant invention areillustrated by, but not limited to, the following: epoxy resins,phenolic resins, polysulfide resins, and elastomers, polyurethane resinsand elastomers, polyamide resins, polyvinylchloride resins, amphorous orcrystalline polyolefins, polyacrylonitrile polymers, silicone polymers,urea-formaldehyde resins, polyether resins and elastomers and the like.

The solid cured polythioether polymer products resulting from theinstant invention have many and varied uses. Examples of some usesinclude but are not limited to adhesives; caulks; elastomeric sealants,coatings, such as wire coatings, electrical circuits cover resists,photoresists and the like, encapsulating or potting compounds, liquidcastable elastomers; thermoset resins, impregnants for fabric, cloth,fibrous webs and other porous substrates; laminating adhesives andcoatings; mastics; glazing compounds; fiberglass reinforced composites;sizing or surface finishing agents, filleting compounds; cured in placegasketing compounds; rocket fuel binders; foamable thermosetting resinsor elastomers; molded articles such as gaskets, diaphragms, ballons,automobile tires, etc.

The molecular weight of the polyenes of the present invention may bemeasured by various conventional methods including solution viscosity,osmotic pressure and gel permeation chromatography. Additionally, themolecular weight may ve calculated from the known molecular weight ofthe reactants.

The viscosity of the polyenes and polythiols may be measured on aBrookfiled Viscometer at 30° or 70° C in accord with the instructionstherefor.

The components to be cured may be prepared as either single-packaged ormulti-packaged liquid polymer systems which may be cured to solidpolythioether elastomers without liberating gaseous by-products whichcause bubbles and voids in the vulcanizate. Thus, there is providedcurable liquid polymer systems composed of polyenes and polythiols inwhich the components individually are storage stable and which are notsensitive to or deteriorated by traces of moisture or oxygen containinggas such as may be encountered during normal storage or handlingprocedures. Solid resinous or elastomeric products may be prepared fromflowable liquid in a system in which the rate of curing may be inhibitedor retarded by the use of chemical inhibitors, antioxidants, and thelike. Conventional curing inhibitors or retarders which may be used inorder to stabilize the components or curable compositions so as toprevent premature onset of curing may include certain acids and bases;hydroquinone; p-tert-butyl catechol; 2,6-di-tert-butyl-p-methylphenol;phenothiazine; N-phenyl-2-naphthylamine; pyrogallol;octadecyl-β-(4-hydroxy-3,5-di-t-butyl phenyl)-propionate; and the like.The cured product may be characterized as in the thermally andoxidatively stable state since there is no reactive carbon-to-carbonunsaturation in the main backbone chain.

As used herein the term polyene and the term polyne refers to single orcomplex species of alkenes or alkynes having a multiplicity of terminalreaction carbon-to-carbon unsaturated functional groups per averagemolecule. For example, a diene is a polyene that has two reactivecarbon-to-carbon double bonds per average molecule. Combinations ofreactive double bonds and reactive triple bonds within the same moleculeare also possible such as for monovinylacetylene which is a polyeneyneunder this definition. For purposes of brevity all these classes ofcompounds are referred to herein as polyenes.

In defining the position of the reactive functional carbon-to-carbonunsaturation, the term terminal is intended to mean that functionalunsaturation is at an end of the main chain in the molecule; whereas bynear terminal is intended to mean that the functional unsaturation isnot more than 10 carbon atoms and typically less than eight carbon atomsfrom an end of the main chain in the molecule. The term pendant meansthat the reactive carbon-to-carbon unsaturation is located terminal ornear-terminal in a branch of the main chain as contrasted to a positionat or near the ends of the main chain. For purposes of brevity all ofthese positions are referred to herein generally as terminalunsaturation.

Functionality as used herein refers to the average number of ene orthiol groups per molecule in the polyene or polythiol, respectively. Forexample, a triene is a polyene with an average of three reactivecarbon-to-carbon unsaturated groups per molecule and thus has afunctionality (f) of three. A dithiol is a polythiol with an average oftwo thiol groups per molecule and thus has a functionality (f) of two.

The mole ratio of ene/thiol groups for preparing the curable compositionis from about 1/0.25 to about 1/4.0 and desirably about 1/0.75 to about1/1.25 group ratio.

The following example will show the improved slip property obtained bythe fatty acid containing pentaerythritol esters of the instantinvention as compared with conventional commercially availablepentaerythritol esters which do not contain the fatty acid moiety. Thestatic and kinetic coefficient of friction was measured in accord withthe procedure set out in ASTMD-1894-63.

EXAMPLE 4

The following formulations were made up and admixed until homogeneous.

    ______________________________________                                        Formulation A              Parts                                              Component                  by Weight                                          Diallyl phthalate          48.8                                               Pentaerythritol tetrakis β-(mercaptopropionate)                                                     48.8                                               Fatty acid containing pentaerythritol ester                                                              10.0                                               product of Example 3                                                          Benzophenone (photocuring rate accelerator)                                                               2.0                                               Antioxidant and thermal stabilizers                                                                       0.4                                               Formulation B              Parts                                              Component                  by Weight                                          Diallyl phthalate          35.5                                               Fatty acid containing pentaerythritol ester                                                              62.4                                               product of Example 3                                                          Benzophenone                2.0                                               Antioxidant and thermal stabilizers                                                                       0.4                                               Formulation C              Parts                                              Component                  by Weight                                          Diallyl phthalate          48.8                                               Pentaerythritol tetrakis β-(mercaptopropionate)                                                     48.8                                               Benzophenone                2.0                                               Antioxidant and thermal stabilizers                                                                       0.4                                               ______________________________________                                    

Each of the above formulations was coated onto two aluminum sheets in anamount equal to 8 mg./4 inches square. The thus coated sheets were thenpassed through a U.V. housing at the rate of 50 feet per minute whereinthey are exposed to U.V. radiation at a surface irradiance of 110milliwatts/cm² from 3 mercury vapor lamps. The aluminum sheets were thensubjected to a second pass under the lamps at the same speed andirradiance. One sheet of each formulation was then subjected to bakingin an air oven for 10 minutes at 375° F. The coefficient of frictionresults are shown in Table I.

                  Table I                                                         ______________________________________                                                      Coefficient of Friction                                                       Static      Kinetic                                             ______________________________________                                        Formulation A   0.224         0.196                                           Formulation A (baked)                                                                         0.196         0.187                                           Formulation B   0.260         0.230                                           Formulation B (baked)                                                                         0.310         0.250                                           Formulation C   0.383         0.374                                           Formulation C (baked)                                                                         0.392         0.350                                           ______________________________________                                    

As can be seen from the results, even the addition of a minor amount ofthe fatty acid-containing pentaerythritol esters (Formulation B) gives amarked improvement in slip as shown by the lower coefficient of frictionas compared to the control (Formulation C) using a conventionalpentaerythritol ester without any fatty acid moiety.

We claim:
 1. A curable composition useful for obtaining a solidpolythioether having improved slip properties comprising:A. a polyenecomponent of the formula:

    [A--X).sub.m

wherein m is an integer of at least 2, wherein X is a member selectedfrom the group consisting of: ##STR19## where h is an integer from 1 to9; R is a radical selected from the group consisting of hydrogen,fluorine, chlorine, furyl, thienyl, pyridyl, phenyl and substitutedphenyl, benzyl and substituted benzyl, alkyl and substituted alkyl,alkoxy and substituted alkoxy, cycloalkyl and substituted cycloalkyl;said substituents on said substituted members selected from the groupconsisting of nitro, chloro, fluoro, acetoxy, acetamide, phenyl, benzyl,alkyl, alkoxy and cycloalkyl; said alkyl and alkoxy having from one tonine carbon atoms and said cycloalkyl having from three to eight carbonatoms; wherein [A] is free of reactive carbon-to-carbon unsaturation;free of highly water-sensitive members; and is a polyvalent chemicallycompatible member of the group consisting of carbonate, carboxylate,carbonyl, ether, silane, silicate, phosphonate, phosphite, phosphate,alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl, aryland substituted aryl, urethane and substituted urethane, urea andsubstituted urea, amine and substituted amine, amide and substitutedamide, hydroxyl, heterocyclic carbon containing radical, and mixturesthereof; said substituents on said members being defined above, saidcomponent having a molecular weight in the range from about 64 to20,000; and a viscosity in the range from essentially 0 to 20 millioncentipoises at 70° C; and, B. pentaerythritol ester component of theformula: ##STR20## wherein n is 0 to 2, and at least 1 and not more than2n + 2 of the A groups are ester radicals of the structure ##STR21##wherein R is a straight chain or branched, saturated or unsaturatedhydrocarbon radical containing 11 to 19 carbon atoms, and at least 2 andnot more than 2n + 3 of the A groups are ester radicals of the structure##STR22## wherein m is 0 to 1 and C. a photosensitizer.
 2. A process forforming a solid, cured polythioether having improved slip propertieswhich comprises admixingA. a polyene component of the formula:

    [A--X).sub.m

wherein m is an integer of at least 2, wherein X is a member selectedfrom the group consisting of: ##STR23## where h is an integer from 1 to9; R is a radical selected from the group consisting of hydrogen,fluorine, chlorine, furyl, thienyl, pyridyl, phenyl and substitutedphenyl, benzyl and substituted benzyl, alkyl and substituted alkyl,alkoxy and substituted alkoxy, cycloalkyl and substituted cyloalkyl;said substituents on said substituted members selected from the groupconsisting of nitro, chloro, fluoro, acetoxy, acetamide, phenyl, benzyl,alkyl, alkoxy and cycloalkyl; said alkyl and alkoxy having from one tonine carbon atoms and said cycloalkyl having from three to eight carbonatoms; wherein [A] is free of reactive carbon-to-carbon unsaturation;free of highly water-sensitive members; and is a polyvalent chemicallycompatible member of the group consisting of carbonate, carboxylate,carbonyl, ether, silane, silicate, phosphate, phosphite, phosphate,alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl, aryland substituted aryl, urethane and substituted urethane, urea andsubstituted urea, amine and substituted amine, amide and substitutedamide, hydroxyl, heterocyclic carbon containing radical, and mixturesthereof; said substituents on said members being defined above, saidcomponent having a molecular weight in the range from about 64 to20,000; and a viscosity in the range from essentially 0 to 20 millioncentipoises at 70° C; B. pentaerythritol ester component of the formula:##STR24## wherein n is 0 to 2, and at least 1 and not more than 2n + 2of the A groups are ester radicals of the structure ##STR25## wherein Ris a straight chain or branched, saturated or unsaturated hydrocarbonradical containing 11 to 19 carbon atoms, and at least 2 and not morethan 2n + 3 of the A groups are ester radicals of the structure##STR26## wherein m is 0 to 1; and C. a photosensitizer, and thereafterexposing the mixture to actinic light.
 3. The process according to claim2 wherein the pentaerithritol ester is ##STR27##
 4. A process forforming a solid, cured polythioether having improved slip propertieswhich comprises admixingA. a polyene component of the formula:

    [A--X].sub.m

wherein m is an integer of at least 2, wherein X is a member selectedfrom the group consisting of: ##STR28## where h is an integer from 1 to9; R is a radical selected from the group consisting of hydrogen,fluorine, chlorine, furyl, thienyl, pyridyl, phenyl and substitutedphenyl, benzyl and substituted benzyl, alkyl and substituted alkyl,alkoxy and substituted alkoxy, cycloalkyl and substituted cycloalkyl;said substituents on said substituted members selected from the groupconsisting of nitro, chloro, fluoro, acetoxy, acetamide, phenyl, benzyl,alkyl, alkoxy and cycloalkyl; said alkyl and alkoxy having from one tonine carbon atoms and said cycloalkyl having from three to eight carbonatoms; wherein [A] is free of reactive carbon-to-carbon unsaturation;free of highly water-sensitive members; and is a polyvalent chemicallycompatible member of the group consisting of carbonate, carboxylate,carbonyl, ether, silane, silicate, phosphonate, phosphite, phosphate,alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl, aryland substituted aryl, urethane and substituted urethane, urea andsubstituted urea, amine and substituted amine, amide and substitutedamide, hydroxyl, heterocyclic carbon containing radical, and mixturesthereof; said substituents on said members being defined above, saidcomponent having a molecular weight in the range from about 64 to20,000; and a viscosity in the range from essentially 0 to 20 millioncentipoises at 70° C; and B. pentaerythritol ester component of theformula: ##STR29## wherein n is 0 to 2, and at least 1 and not more than2n + 2 of the A groups are ester radicals of the structure ##STR30##wherein R is a straight chain or branched, saturated or unsaturatedhydrocarbon radical containing 11 to 19 carbon atoms, and at least 2 andnot more than 2n + 3 of the A groups are ester radicals of the structure##STR31## wherein m is 0 to 1, and thereafter exposing the mixture tohigh energy ionizing radiation.
 5. The process according to claim 4wherein the penthaerythritol ester is ##STR32##
 6. The composition ofclaim 1 as a coating on a substrate.